At times, it is not necessary to capture high-resolution images and/or high frame rate series of images, even when the camera/image sensor may be capable of capturing more many pixels per image and/or per time than needed. For example, some applications only need to have the essence of an image or series of images captured for processing or the like, such as significant features, rather than capture a large number of pixels. One such application is continuous mobile vision, which is generally directed towards capturing and processing a user's visual experience in real-time, on the go.
Contemporary image sensors that are widely-used in mobile systems and personal computers are not energy proportional; that is, when frame rate, resolution and/or number of bits per pixel is lowered, the energy consumption does not proportionally decrease, and indeed, the energy increase per pixel is inversely proportional to the image quality, often significantly. This leads to inefficient operation even when the image sensor is operating with low output image quality. For example, camera applications such as computer vision and augmented reality applications are not able to trade quality for improved battery lifetime.